The instant invention relates generally to optically pumped lasers, and more particularly to the use of exploding films for pumping atomic and molecular lasing systems.
Certain lasers can be pumped by a variety of high-intensity light sources, both coherent and noncoherent. Included among the latter sources are xenon flashlamps which have notably long lifetimes, substantial reliability and a good match of their spectral emission with visible or near-ultraviolet bands of many laser media. Brightness temperatures of such sources are typically 6-12 kK and efficiencies for conversion of electrical energy into broadband radiant energy can be as high as 0.8. Other noncoherent sources for optical pumping have been recently introduced. Exploding-wire discharges, surface discharges, ablating-wall flashlamps, plasmadynamic discharges, magnetoplasma compressors and ordinary discharges resulting from a z-pinch have been successfully utilized to pump lasers. The introduction of new laser media and changing requirements for older laser media have precipitated development of, or adaptation of, these newer light sources. Most of the above-mentioned sources have the capability of producing much greater light intensity than xenon flashlamps, especially in the ultraviolet region of the electromagnetic spectrum. This derives from the considerably higher blackbody temperatures of these sources (approximately 30 kK). Lasers requiring excitation in the ultraviolet region of the spectrum especially benefit from the higher brightness temperatures, since the peak emission for a 30 kK blackbody occurs near 100 nm. Many of these sources do not require envelopes, allowing vacuum ultraviolet radiation to be efficiently deposited in the laser medium. Another advantage of these sources, in addition to brightness and spectral content is their shorter pulselengths. This leads to greater peak optical powers than can be delivered by the xenon flashlamps.
Although exploding-wire discharges have been extensively investigated as optical pumping sources for lasers, the use of exploding conducting films or foils has not received attention as an optical pumping technique for any type of laser. The reported temperature range for such discharge sources is between 15 and 40 kK. In "Layered Pulsed Discharge as a Light Source," by I. V. Dvornikov, Yu. N. Kolpakov, V. A. Lakutin, and I. V. Podmoshenskii, translated from Zhurnal Prikladnoi Spektroskopii 21, 227 (1974), in "Structure and Emission of a Stratified Pulsed Discharge," by V.A. Lakutin, V. I. Demidov, I. V. Podmoshenskii, and V. F. Sobolev, Sov. Phys. Tech. Phys. 23, 1020 (1978), in "Stratified Pulsed Discharge with Limited Surface Area," by V. E. Lavrentyuk, V. A. Lakutin, I. V. Podmoshenskii and V. F. Sobolev, Sov. Phys. Tech. Phys. 24, 1186 (1979), in "Microsecond Stratified Pulsed Discharge," by V. A. Lakutin, I. V. Podmoshenskii, Yu. A. Rymarchuk, and V. V. Sudarikov, Sov. Phys. Tech. Phys. 24, 1191 (1979), and in "Initial Stage of a Laminar Pulsed Discharge," by V. A. Lakutin, I. V. Podmoshenskii and V. F. Sobolev, Sov. Phys. Tech. Phys. 25, (1980), details of the characteristics of discharges from exploding metal foils are presented. Mention is made in all of these journal articles that this type of discharge might be used as a source of light, but there is no disclosure as to how such a light source would be applied to the pumping of gas lasers as is taught by the instant invention. Moreover, the above-referenced articles only teach the use of foils and not the use of conducting films as taught in the subject invention. Further, in U.S. Pat. No. 3,646,471 for a "A Cylindrical Array of Exploding Conductors Embedded in a Solid Dielectric for Pumping a Laser," issued to Jack DeMent on Feb. 29, 1972, the inventor discloses an apparatus for providing a multiplicity of light pulses for pumping a laser. The explodable conductors described may include metal foils and films. However, the embodiments described therein and the teachings thereof are directed to the external pumping of gain media as opposed to the placement of the exploding conducting film in the gain medium itself, thereby avoiding transmission difficulties of the short wavelength electromagnetic radiation of interest through window materials.
In "Optically Pumped Ultraviolet and Infrared Lasers Driven by Exploding Metal Films and Wires," by C. R. Jones and K. D. Ware, Proceedings of the Los Alamos Conference an Optics '83, SPIE Volume 380, page 160, published on Nov. 21, 1983, the disclosure of which is hereby incorporated by reference herein, and in "High-Energy Ultraviolet I.sub.2 Laser," by C. R. Jones, K. D. Ware and O. F. Swenson, AIP Conference Proceedings, No. 100, Excimer Lasers-1983, page 116, published on June 27, 1983, the disclosure of which is hereby incorporated by reference herein, the use of exploding metal films for pumping molecular and atomic iodine lasers is taught. The subject invention derives in part from the experiments disclosed therein.